1. Field of the Invention
The present invention relates to an apparatus and method for collecting, mixing and reintroduction with the stored cold portions of various household hot water streams the residues of various drinking water purification processes like reverse osmosis in order to accumulate the mix for subsequent less restrictive cold water use.
2. Description of the Prior Art
With increasing population density prudence in the use of the world's resources has become a dominant concern. One resource that is central to all the functions of life is clean water, a resource that is growing scarce and is therefore now the primary concern of most municipalities. Simply, the availability of fresh water now limits most municipal growth and virtually all current housing expansions are associated with costly water recycling and other conservation measures, a cost exchange that will only continue to rise in a world that increases in its mean temperature.
For a long time it has been recognized that the primary component of unnecessary water waste is the early, cool part of a hot water stream that is currently just dumped down the drain until the desired stream temperature is reached. In multiple dwelling structures these losses can become quite large and basic economics have therefore compelled some conservation, like the use of continuously circulating hot water loops which shorten substantially the length, and therefore the volume, of the several branch circuits feeding each hot water valve. While these continuously circulating arrangements have resulted in substantial savings in the daily water use, it is at the cost of electricity to circulate the flow. Moreover, the sheer number of the various circuits branching from the loop results in significant waste of water nonetheless.
The next significant component of fresh water waste is the waste associated with various purification techniques to obtain drinking water, and particularly those effected by reverse osmosis, in which some of the matter that is entrained in the municipal water flow is separated from the stream dedicated for drinking. Most of these processes seek to remove unwanted mineral and pathogenic matter from the drinking water stream and therefore require substantial dilution ahead of the filtering or reverse osmosis membrane to enable the continuing functioning of the process itself. In the course of such dilution large quantities of water, with only somewhat higher concentrations, are again simply washed down the drain.
Accordingly, both the temperature rise time of the household washing streams and also the dilution of the source water needed for purification result in large quantities of wasted water in a household which, once contained and stored, can be dedicated for use in washing or other sanitary functions like flushing the toilet. Significantly, since both these waste streams rarely coincide in time the waste stream associated with raising the water temperature at the shower head becomes useful to dilute even further the source water concentrations in front of the various osmosis or filtering membrane once both are collected in the several storage accumulating containers. Thus both conservation mechanisms may be synergistically combined to optimize both functions.
In the past various mechanisms have been proposed that in one way or another divert the unwanted portions of a water stream into an accumulator or other storage cavity to be saved and thereafter drained with the cold water flow as cold water is demanded. While suitable for the purposes intended these prior mechanisms fail to fully resolve the volumetric requirements of storage and also the functioning of the conserving process itself against the high back pressures of various flow restrictors that therefore the necessary household space burden devoted thereto.
Those skilled in the art, of course, will appreciate that an exactly paired hot water—cold water demand sequence is rare in a household. Similarly, it is wholly unlikely that the waste stream associated with raising the washing flow temperature will match exactly the dilution cycles associated with drinking water purification, but the former will, in fact, prevail. This prevalence, together with the statistical nature of both, suggests a somewhat larger accumulation volume since any practical implementation will need a volumetric storage capacity surplus that will accommodate several unmatched sequences in a row in order to be useful since a full storage reservoir cannot provide the needed diversion volume for either function. In a busy household where the sequential morning hot water demands often exceed the water heater capacity, and little or no cold water is added to cool the stream, a practically sized accumulator needs to accommodate several hot water transients each of a volume equal to the volume of the utilized plumbing branch. Of course, the potential drinking water demands that are interspaced between these cycles only add to the needed storage volume.
Moreover, the calculus of reservoir volume must also consider the efficacy of the reservoir draining process itself, a process effected when cold water is needed either in filtering the drinking stream or in the cold water side of a faucet, and to obtain full benefit thereof this draining rate needs to be maximized to the full cold water flow demanded. But then, the same water use conservation concerns have also fostered various flow restriction mechanisms throughout the household, thus limiting the usefulness of any drainage mechanism in which the draining flow is entrained with, and/or carried along by, the primary cold water flow. More importantly, these flow restrictions reduce the available pressure differentials for any accumulator response and for dispensing of the water thus collected, thereby imposing the need for the pressure compensation thereof which is neither suggested nor taught at all in the art.
The foregoing volumetric concerns are not the whole of it. Like in any statistical process the probabilities of long sequences of uninterrupted repeating water demands of one kind are sufficiently significant that even a very large reservoir sizing will be quickly exceeded. To accommodate these real possibilities the water conserving system will either need to include very large and therefore costly reservoirs or must automatically revert to a by-passing state in order to retain the original basic water supply functions.
While some of these concerns may have had individual attention in the prior art, the complete systematic combination of all these notions has not been fully considered. For example U.S. Pat. No. 4,697,614 to Powers et al., while teaching a diversion into the accumulator of the initial hot water stream, does so by a manually effected selector. The collected water in the accumulator is thereafter drained by entrainment with a reduced pressure cold water flow. While suitable for the purposes intended this particular arrangement demands manual attention to effect its use while also protracting the accumulator drainage by the reduced flow therefrom.
By further example U.S. Pat. Nos. 5,339,859 and 5,452,740, both issued to Bowman, while each replacing the manual selector with a temperature sensing flow control in the hot water circuit, similarly fail to optimize the draining part of the process, with the '740 patent resolving the drainage paradox by directing the accumulated water to irrigate plants. While once more each of these references, and the many others, achieve their respectively intended purposes, the central concern of a convenient, fully automated conservation arrangement that accommodates the varied household functions at grossly limited pressure differentials has not been fully addressed.
It will be appreciated that any demand increases on the municipal water supply, particularly at the currently exacerbated population density levels, will often result in some degradation in the quality of the water itself. Simply, while safe pathogen levels must always be attained, in a stressed setting little reserve is available to attend to matters of taste and household purification systems of drinking water are therefore on the rise. The full conservation aspects of a typical household require attention to the complex interplay of all these several concerns. An automated system that synergistically combines these several functions into a complementing fully automated arrangement conformed to operate in a virtually imperceptible manner is therefore extensively desired and it is one such system that is disclosed herein.